Optical fibers are being used with increasing regularity for the transmission and processing of optical signals. A number of devices have been developed to couple light between optical fibers, to modulate optical signals in optical fibers, to amplify optical signals in optical fibers, and the like. However, a need exists for a in-line device for reversing the direction of optical signals in optical fibers without splicing the optical fiber. Additionally, a need exists for a frequency sensitive reflector which can be used as a component of an optical fiber system, such as a communications network.